FCC Exam Question: 34D5

What are the characteristics of the SART transmitted signal?

A. It starts with a sweep of 10.2 usec.followed by a sweep of 0.6 usec for a total of 10 sweeps.
B. It starts with a sweep of 0.8 usec followed by a sweep of 12.6 usec for a total of 12 sweeps.
C. It starts with a sweep of 0.4usec across the entire 3 cm radar band followed by a returning sweep of 7.5 usec
D. It starts with a sweep of 8.5 usec followed by a sweep of 0.4 usec for 10 sweeps.
Correct Answer: C

Explanation: A Search and Rescue Transponder (SART) operates by responding to X-band (3 cm) marine radar signals. When interrogated by a radar pulse, the SART transmits a distinctive signal to appear on the interrogating radar's display. The characteristic SART transmitted signal begins with a very fast 0.4 microsecond (µs) sweep across the entire 3 cm radar band (approximately 9.2-9.5 GHz). This is immediately followed by a slower, returning sweep of 7.5 µs back across the band. This unique frequency modulation pattern, repeated several times (typically 12 sweeps for the full response), creates a line of 12 equally spaced dots radiating outward from the SART's position on the radar screen. This pattern clearly distinguishes a SART from other radar targets or clutter, indicating a distress situation. Options A, B, and D describe incorrect sweep durations, patterns, or numbers of sweeps, which would not produce the internationally recognized SART display on a radar.

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Includes Elements 1, 3, 6, 7R, 8, and 9.